CN109664953B

CN109664953B - System and method for controlling active aerodynamic components

Info

Publication number: CN109664953B
Application number: CN201811136828.4A
Authority: CN
Inventors: T·D·德梅特里奥; J·R·奥登; F·P·米尔斯特菲尔德
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2017-10-16
Filing date: 2018-09-28
Publication date: 2021-12-10
Anticipated expiration: 2038-09-28
Also published as: US10618573B2; DE102018125522A1; CN109664953A; US20190111979A1

Abstract

A motor vehicle includes a vehicle body. A movable member with a first position and a second position having different aerodynamic profiles is disposed on an exterior of the vehicle body. An actuator is coupled to the movable member and configured to actuate the movable member between a first position and a second position. The sensor is configured to detect a relative road load between the second aerodynamic profile and the first aerodynamic profile during a driving cycle. The controller is configured to control the actuator to move the movable member to the first position in response to satisfaction of the first operating condition, to control the actuator to move the movable member to the second position in response to satisfaction of the second operating condition, and to control the actuator to move the movable member to the first position in response to the relative road load being positive during the drive cycle.

Description

System and method for controlling active aerodynamic components

Technical Field

The present disclosure relates to motor vehicles, and more particularly to aerodynamic features of motor vehicles.

Background

A motor vehicle disturbs the air it passes through while driving. This air disturbance has, among other things, an effect on the energy consumption of the motor vehicle. Overcoming the wind resistance and turbulence created by the passage of the vehicle consumes energy that must be derived from the vehicle's fuel, electricity, or other stored energy. The greater the windage and turbulence, the greater the fuel consumption and the lower the fuel economy. Accordingly, aerodynamic performance is typically considered in designing a vehicle. In conventional vehicle designs, the aerodynamic feature is typically a fixed body structure external to the vehicle. More recently, however, actively movable aerodynamic features have been implemented on some vehicles.

Disclosure of Invention

A motor vehicle according to the present disclosure includes a vehicle body and a movable member disposed on an exterior of the vehicle body. The movable member has a first position and a second position. The first location has a first aerodynamic profile and the second location has a second aerodynamic profile different from the first aerodynamic profile. The vehicle additionally includes an actuator coupled to the movable member. The actuator is configured to actuate the movable member between a first position and a second position. The vehicle also includes a sensor configured to detect a relative road load between the second aerodynamic profile and the first aerodynamic profile during a driving cycle. The vehicle also includes a controller configured to control the actuator to move the movable member to the first position in response to the first operating condition being met, to control the actuator to move the movable member to the second position in response to the second operating condition being met, and to control the actuator to move the movable member to the first position in response to the relative road load being positive during the drive cycle.

In an exemplary embodiment, the second operating condition includes vehicle acceleration being below a calibrated acceleration threshold and vehicle speed being above a calibrated speed threshold.

In an example embodiment, the first operating condition comprises a detected vehicle speed, and the controller is configured to control the actuator to move the movable member to the first position based on an actuator setting obtained from a look-up table based on the detected vehicle speed.

In an exemplary embodiment, the actuator is configured to continuously actuate the movable member between the first and second positions.

In an exemplary embodiment, the movable member has a third position having a third aerodynamic profile that is different from the first aerodynamic profile and the second aerodynamic profile. In such embodiments, the actuator is further configured to actuate the movable member to the third position, and the controller is further configured to control the actuator to move the movable member to the third position in response to the relative road load being negative.

A method of controlling a vehicle according to the present disclosure includes detecting a first vehicle operating condition and, in response to detecting the first vehicle operating condition, automatically controlling, via a controller, an actuator coupled to an active aerodynamic device to a first setting. The method also includes detecting a second vehicle operating condition, and automatically controlling, via the controller, the actuator to a second setting in response to detecting the second vehicle operating condition with the actuator in the first setting. The method also includes determining, via the controller, a relative road load between the second setting and the first setting, and automatically controlling, via the controller, the actuator to the first setting in response to the relative road load being positive.

In an exemplary embodiment, the actuator is configured to actuate continuously between the first and second settings.

In an exemplary embodiment, the method further comprises automatically controlling the actuator via the controller to a third setting in response to the relative road load being negative, wherein the second setting is between the first setting and the third setting. Such embodiments may also include determining, via the controller, a second relative road load between the third setting and the second setting, and automatically controlling, via the controller, the actuator to the second setting in response to the second relative road load being positive. Such embodiments may include storing the second setting in a non-volatile vehicle memory for access during a subsequent driving cycle.

In an exemplary embodiment, the method further comprises automatically controlling, via the controller, the actuator to a third setting, wherein the first setting is between the third setting and the second setting. Such embodiments may also include determining, via the controller, a second relative road load between the third setting and the second setting, and automatically controlling, via the controller, the actuator to the first setting in response to the second relative road load being positive.

An active aerodynamic system according to the present disclosure includes a movable member disposed outside a vehicle. The movable member has a first position and a second position different from the first position. The system additionally includes an actuator coupled to the movable member and configured to actuate the movable member between the first position and the second position. The system also includes a sensor configured to detect a relative road load between the second position and the first position during a driving cycle. The system also includes a non-transitory data store provided with actuator calibration. The system also includes a controller. The controller is configured to control the actuator during a drive cycle to move the movable member to the first position based on the actuator calibration. The controller is further configured to automatically control the actuator to the second position in response to the vehicle being in a steady state and the movable member being in the first position. The controller is further configured to modify the actuator calibration based on the second position in response to the relative road load being negative.

Embodiments in accordance with the present disclosure provide a number of advantages. For example, systems and methods according to the present disclosure may provide on-board optimization of calibration for active aerodynamic devices, thereby reducing the time and expense associated with such calibration using wind tunnel experiments or simulations. Further, the systems and methods according to the present disclosure may modify the calibration for the active aerodynamic device as needed in response to changes in aerodynamic performance (e.g., attachment of a trailer to a vehicle).

The above advantages and other advantages and features of the present disclosure will become apparent from the following detailed description of the preferred embodiments, when taken in conjunction with the accompanying drawings.

Drawings

FIG. 1 is a schematic illustration of a vehicle according to an embodiment of the present disclosure;

FIG. 2 is a diagrammatic view of an active aerodynamic device according to a first embodiment of the present disclosure;

FIGS. 3A and 3B are diagrammatic views of an active aerodynamic device according to a second embodiment of the present disclosure; and is

FIG. 4 is a flowchart illustration of a method of controlling an active aerodynamic device according to an embodiment of the disclosure.

Detailed Description

Embodiments of the present disclosure are described herein. However, it is to be understood that the disclosed embodiments are merely examples and that other embodiments may take various and alternative forms. The drawings are not necessarily to scale; some functions may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. As one of ordinary skill in the art will appreciate, various features illustrated and described with reference to any one of the figures may be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combination of features shown provides a representative embodiment of a typical application. However, various combinations and modifications of the features consistent with the teachings of the present disclosure may be required for particular applications or implementations.

One or more active aerodynamic devices may be provided for a motor vehicle. Active aerodynamic devices refer to aerodynamic components that can be actuated between a plurality of different positions exhibiting different aerodynamic profiles. Thus, the active aerodynamic device may be actuated during a driving cycle to change an aerodynamic property of the vehicle, such as a resistance or a downforce.

Referring now to FIG. 1, a schematic illustration of a vehicle 10 according to the present disclosure is shown. The vehicle 10 includes a powertrain 12. In the exemplary embodiment, power system 12 includes an internal combustion engine; however, in other embodiments, power system 12 may have other configurations, such as a purely electric or fuel cell power system. The vehicle 10 additionally includes at least one sensor 14. In the exemplary embodiment, at least one respective sensor 14 is configured to detect a road load of vehicle 10. In the embodiment illustrated in FIG. 1, at least one of the sensors 14 is associated with the power system 12. In the illustrated embodiment, the sensor 14 may include: a fuel flow sensor configured to monitor fuel consumption of power system 12, a torque sensor configured to monitor torque output by power system 12, or other sensors configured to otherwise monitor a load on power system 12. However, in other embodiments, other sensors capable of monitoring road loads may be implemented. In addition, the sensors 14 may include additional sensors, such as a vehicle speed sensor, a steering position sensor, and an accelerometer.

The vehicle 10 additionally includes at least one active aerodynamic system 24, the active aerodynamic system 24 including at least one movable aerodynamic member 16. The active aerodynamic system 24 may include an active rear wing as will be discussed in further detail below with reference to fig. 2, an active underbody air deflector as will be discussed in further detail below with reference to fig. 3, other active aerodynamic devices, or combinations thereof. The movable aerodynamic member 16 is movable between a plurality of different positions. The active aerodynamic system 24 includes at least one actuator 18, the actuator 18 being coupled to the movable aerodynamic member 16 and configured to move the movable aerodynamic member 16 between a plurality of positions. The actuator 18 may include a linear actuator, an electric motor, a smart material actuator, any other suitable actuator, or a combination thereof.

The power system 12, sensors 14, and actuators 18 are in communication with or under the control of a controller 20. Although depicted as a single unit, the controller 20 may include one or more additional controllers, collectively referred to as "controllers". The controller 20 may include a microprocessor or Central Processing Unit (CPU) in communication with various types of computer-readable storage devices or media. The computer readable storage device or medium may include volatile and non-volatile memory such as Read Only Memory (ROM), Random Access Memory (RAM), and Keep Alive Memory (KAM). The KAM is a persistent or non-volatile memory that can be used to store various operating variables when the CPU is powered down. The computer-readable storage device or medium may be implemented using any of a number of known memory devices, such as PROMs (programmable read Only memory), EPROMs (electronic PROM), EEPROMs (electrically erasable PROM), flash memory, or a combination memory device capable of storing data, some of which represent executable instructions used by a controller to control an engine or vehicle.

The controller 20 communicates with a non-transitory data storage medium 22. The data storage medium 22 is provided with control information for controlling the actuator 18, which will be discussed in further detail below. In the exemplary embodiment, the control information includes a look-up table having default actuator settings based on one or more vehicle parameters detectable by sensor 14, such as vehicle speed, acceleration, and cornering.

Referring now to FIG. 2, an isometric view of an exemplary active aerodynamic device 24 'for a motor vehicle 10' is shown. In this embodiment, the active aerodynamic device 24 'may be referred to as a rear wing 24'; however, other embodiments within the scope of the present disclosure include other types of active aerodynamic devices. The rear wing 24 'is coupled to a rear portion 28 of the vehicle 10' by at least one strut 26. The aft wing 24 'includes an elongated aerodynamic member or airfoil 16'. The airfoil 16' has a suction surface 30 facing the ground plane and a pressure surface 32 facing away from the ground plane. Thus, as air flows over the airfoil 16 ', a pressure differential is created between the pressure surface 32 and the suction surface 30, and a downforce is exerted on the rear 28 of the vehicle 10'.

At least one actuator 18 ' is arranged to pivot the airfoil 16 ', for example, to adjust the angle of attack of the airfoil 16 '. According to various embodiments, the actuator 18 'may be configured to pivot the airfoil 16 relative to the strut 26, to pivot a portion of the strut 26 relative to another portion of the strut 26, or other suitable configuration for adjusting the angle of attack of the airfoil 16'. The actuator 18 ' may be controlled by the controller 20 ' to pivot the airfoil 16 ' between different positions during a driving cycle in response to, for example, vehicle speed and lateral acceleration. By pivoting the airfoil 16 ', the downforce and drag generated by the airfoil 16' may be modified based on current operating conditions.

Referring now to fig. 3A and 3B, a view of a second exemplary active aerodynamic device 24 "for a motor vehicle 10" is shown. In the embodiment of fig. 3A and 3B, the vehicle 10 "is provided with an active aerodynamic device 24", which may be referred to as an air deflector 24 ". The air deflector 24 "includes a movable member 16" coupled to the actuator 18. The actuator 18 "is configured to pivot the movable member 16" about a generally horizontal pivot axis extending transversely through the vehicle. The actuator 18 "is under the control of the controller 34". The controller is configured to control the actuator 18 "to move the movable member 16" between the blocking position (as shown in fig. 3A) and the cooling position (as shown in fig. 3B). In the blocking position, the air deflector 24 "acts as an air dam, blocking the passage of air beneath the vehicle 10", thereby reducing drag. In the cooling position, the movable member 16 "pivots to assume different blocking modes, deflecting air towards the wheels, thereby increasing the cooling of the vehicle brakes.

Known active aerodynamic systems are controlled according to a predefined calibration scheme, e.g. a look-up table comprising actuator settings corresponding to velocity or acceleration values. Calibration schemes are typically designed for preferred characteristics at given operating conditions, such as reduced resistance or increased downforce. The optimal actuator settings are influenced by various vehicle factors, such as body type, suspension, tires, wheel base, and therefore are specific to a particular variant of the vehicle. The predefined calibration scheme is typically determined based on wind tunnel testing or simulation. However, this calibration process can be relatively time intensive as the test or simulation is repeated for each new vehicle or new variation of vehicles. Furthermore, calibration is typically defined for vehicles under normal operating conditions and may not take into account factors that may alter real world aerodynamic performance, such as the presence of a trailer.

Referring now to FIG. 4, a method of controlling a vehicle is shown in flowchart form, according to an embodiment of the present disclosure. The algorithm starts at block 100.

As shown in block 102, current vehicle parameters are detected. Vehicle parameters may be detected by one or more sensors, including but not limited to a vehicle speed sensor, a steering position sensor, and an accelerometer. In an exemplary embodiment, the vehicle parameters include speed, acceleration, and cornering. Other parameters or combinations of parameters may be measured in other embodiments.

The active aerodynamic device is controlled according to the current calibration, as shown in block 104. This may include controlling the actuators to settings obtained from the look-up table based on the vehicle parameters detected at block 102. If the algorithm was not previously run, the current calibration may be a default calibration provided by the vehicle manufacturer. If the algorithm is already running, the current calibration may be modified relative to the default calibration, which will be discussed in further detail below.

As shown in operation 106, it is determined whether the vehicle is traveling at a high speed and is in substantially steady state operation. In an exemplary embodiment, the determination includes determining whether the current vehicle acceleration is below a predetermined threshold, wherein the vehicle speed is above the predetermined threshold.

If the determination of operation 106 is negative, control returns to block 102. The active aerodynamic device is thus controlled according to the current calibration unless and until the vehicle is in substantially steady state operation.

If the determination of operation 106 is positive, the active aerodynamic device is incremented in a first direction relative to the current calibration, as shown in block 108. In an exemplary embodiment, this is performed by controlling the actuator to a more extended or more retracted setting relative to the current calibration.

Vehicle road loads are monitored during changes in aerodynamic device position, as shown in block 110. This may include, for example, monitoring fuel consumption rate or engine torque. A reduction in specific fuel consumption or engine torque may correspond to a reduction in road load and also to a reduction in drag and a more desirable location of the active aerodynamic device under current operating conditions.

It is determined whether the current active aerodynamic device position has a negative relative road load as compared to the previous active aerodynamic device position, i.e., a lower road load than the previous active aerodynamic device position, as indicated at block 112. If the determination is positive, control returns to block 108. Thus, the active aerodynamic device is increased in the first direction until the road load is no longer reduced.

If the determination is negative, the first minimum road load and position are stored, as indicated at block 114. The first minimum road load and position corresponds to a minimum road load value measured as the active aerodynamic device sweeps in a first direction and corresponds to an active aerodynamic device position at which the road load value was obtained.

The active aerodynamic device is then returned to the position according to the current calibration, as indicated by block 116. As described above, this may include controlling the actuators to settings obtained from the look-up table based on the vehicle parameters detected at block 102.

The active aerodynamic device is incremented in a second direction relative to the current calibration, as shown in block 118. In an exemplary embodiment, this is performed by controlling the actuator in the opposite direction with respect to block 108.

As shown in block 120, vehicle road load is monitored during the change in aerodynamic device position. As described above, this may include, for example, monitoring fuel consumption rate or engine torque.

It is determined whether the current active aerodynamic device position has a negative relative road load as compared to the previous active aerodynamic device position, i.e., a lower road load than the previous active aerodynamic device position, as indicated at block 122. If the determination is positive, control returns to block 118. Thus, the active aerodynamic device is increased in the first direction until the road load is no longer reduced.

If the determination is negative, then the second minimum road load and position are stored, as indicated at block 124. The second minimum road load and position corresponds to a minimum road load value measured as the active aerodynamic device sweeps in the second direction and corresponds to the active aerodynamic device position at which the road load value was obtained.

The active aerodynamic device is then controlled to a minimum road load position between the first storage position and the second storage position, as indicated by block 126. Thus, if the first minimum road load is less than the second minimum road load, the active aerodynamic device is controlled to the first position. Likewise, if the second minimum road load is less than the first minimum road load, the active aerodynamic device is controlled to a second position. Thus, regardless of the current calibration, the active aerodynamic device is controlled to a position corresponding to the minimum measured road load.

The calibration of the active aerodynamic device is then updated, as indicated by block 128. In an exemplary embodiment, this is performed by modifying a look-up table containing actuator settings based on current operating parameters. In some such embodiments, the updating may be performed by calculating an offset or multiplier between the location corresponding to the minimum measured road load and the current calibration. The calculated offset or multiplier is then applied to a plurality of settings in a look-up table to establish an updated calibration for a range of potential operating parameters. In other such embodiments, only the settings based on the current operating parameters are modified, resulting in more limited and more detailed updates to the lookup table.

The algorithm then terminates at block 130.

In the above variation, steps 108 to 126 may be repeated one or more times for verification purposes before updating the calibration at block 128.

In another variation, the algorithm shown in fig. 4 may be executed only in response to a learning mode condition being met, e.g., the operator selecting a learning mode, or the odometer reading being below a predetermined threshold corresponding to an initialization period.

In yet another variation, the calibration update performed in block 128 continues only for the duration of the current driving cycle, after which the calibration reverts to the default calibration. Thus, the algorithm can accommodate transient changes in the aerodynamic performance of the vehicle, such as the attachment of a trailer to the vehicle.

In a vehicle having multiple active aerodynamic devices, the algorithm shown in FIG. 4 may be performed individually for each active aerodynamic device on the vehicle.

It can be seen that a system and method for on-board optimization of calibration of an active aerodynamic device is provided in accordance with embodiments of the present disclosure, thereby reducing the time and expense associated with calibrating such calibration using wind tunnel experiments or simulations. Further, the system and method according to the present disclosure may modify the calibration for the active aerodynamic device in response to changes in aerodynamic performance (e.g., attachment of a trailer to a vehicle) as needed.

As previously mentioned, the features of the various embodiments may be combined to form further embodiments of the invention, which may not be explicitly described or illustrated. While various embodiments may be described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art will recognize that one or more features or characteristics may be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes may include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, and the like. Accordingly, embodiments described as being less desirable with respect to one or more characteristics than other embodiments or prior art implementations are not outside the scope of the present disclosure and may be desirable for particular applications.

While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. As previously mentioned, the features of the various embodiments may be combined to form further embodiments of the invention, which may not be explicitly described or illustrated. While various embodiments may be described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art will recognize that one or more features or characteristics may be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes may include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, and the like. Accordingly, embodiments described as being less desirable with respect to one or more characteristics than other embodiments or prior art implementations are not outside the scope of the present disclosure and may be desirable for particular applications.

Claims

1. A motor vehicle comprising:

a vehicle body;

a movable member disposed outside the vehicle body, the movable member having a first position and a second position, the first position having a first aerodynamic profile and the second position having a second aerodynamic profile that is different from the first aerodynamic profile;

an actuator coupled to the movable member and configured to actuate the movable member between the first position and the second position;

a sensor configured to detect relative road loads during a change between the second aerodynamic profile and the first aerodynamic profile during a driving cycle;

a controller configured to control the actuator to move the movable member to the first position in response to a first operating condition being met, to move the movable member to the second position in response to a second operating condition being met, and to move the movable member to the first position in response to the relative road load being positive, the movable member having a third position between the first and second positions, the third position having a third aerodynamic profile different from the first and second aerodynamic profiles, the controller further configured to control the actuator to move the movable member to the third position in response to the relative road load being negative.

2. A motor vehicle in accordance with claim 1, wherein the second operating condition includes vehicle acceleration being below a calibrated acceleration threshold and vehicle speed being above a calibrated speed threshold.

3. A motor vehicle in accordance with claim 1, wherein said first operating condition comprises a detected vehicle speed, and wherein said controller is configured to control said actuator to move said movable member to said first position based on an actuator setting obtained from a look-up table based on said detected vehicle speed.

4. A motor vehicle in accordance with claim 1, wherein said actuator is configured to actuate said movable member continuously between said first position and said second position.

5. A motor vehicle in accordance with claim 1, wherein said sensor comprises a fuel flow sensor configured to monitor fuel consumption or a torque sensor configured to monitor torque output.